Operational control of multiple valves in a well

ABSTRACT

A method of controlling operation of multiple valves interconnected in a tubular string in a subterranean well can include opening each of the valves, and then closing the valves in response to an application of pressure to the tubular string. A well system can include multiple valves interconnected in a tubular string, each of the valves including an actuator, and a valve control device interconnected in the tubular string. The valve control device may be connected to each of the valve actuators via multiple flow paths, whereby a pressure differential generated between the flow paths is also generated in each of the valve actuators.

BACKGROUND

This disclosure relates generally to equipment utilized and operations performed in conjunction with a subterranean well and, in an example described below, more particularly provides for operational control of multiple valves in a well.

It is sometimes beneficial to be able to open each of multiple valves in succession in a well. For example, it is desirable in some cases to individually stimulate each of multiple zones traversed by a wellbore, so that optimum pressure and flow of stimulation fluids can be delivered to each zone. For this purpose, multiple valves which can be individually opened may be interconnected in a casing, liner or tubing string.

Unfortunately, if subsequent stimulation operations are needed for the zones, it is typically inconvenient, time-consuming and expensive to close the open valves. Therefore, it will be appreciated that improvements are needed in the art of operational control of multiple valves in a well.

SUMMARY

In the disclosure below, well systems and associated methods are provided which bring improvements to the art of operational control of multiple valves in a well. One example is described below in which the valves can be conveniently closed after having been opened. Another example is described below in which multiple valves can be opened and/or closed together.

In one aspect, a method of controlling operation of multiple valves interconnected in a tubular string in a subterranean well is provided to the art by this disclosure. The method can include opening each of the valves, and then closing the valves in response to an application of pressure to the tubular string.

In another aspect, the disclosure provides a well system to the art. The well system can include multiple valves interconnected in a tubular string, each of the valves including an actuator, and a valve control device interconnected in the tubular string. The valve control device may be connected to each of the valve actuators via multiple flow paths, whereby a pressure differential generated between the flow paths is also generated in each of the valve actuators.

These and other features, advantages and benefits will become apparent to one of ordinary skill in the art upon careful consideration of the detailed description of representative examples below and the accompanying drawings, in which similar elements are indicated in the various figures using the same reference numbers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic partially cross-sectional view of a well system and associated method embodying principles of the present disclosure.

FIGS. 2A & B are enlarged scale cross-sectional views of successive axial sections of a valve which may be used in the system and method of FIG. 1.

FIG. 3 is an enlarged scale schematic cross-sectional view of a valve control device which may be used in the system and method of FIG. 1.

FIG. 4 is a further enlarged scale schematic cross-sectional view of another configuration of the valve control device having a flow path reversing plug installed therein.

FIG. 5 is a schematic cross-sectional view of yet another configuration of the valve control device having a flow path testing plug installed therein.

DETAILED DESCRIPTION

Representatively illustrated in FIG. 1 is a well system 10 and associated method which embody principles of this disclosure. In the well system 10, multiple valves 12 (indicated in FIG. 1 as elements 12 a-d) are interconnected in a tubular string 14. The tubular string 14 could be a casing, liner, tubing or other type of tubular string.

The valves 12 are used to control flow between the interior of the tubular string 14 and each of corresponding multiple zones 16 (indicated in FIG. 1 as elements 16 a-d) intersected by a wellbore 18. The wellbore 18 is depicted in FIG. 1 as being uncased or open hole, but the wellbore could be cased or lined in other examples.

Packers 20 are used to isolate the zones 16 from each other in the wellbore 18. Representatively, the packers 20 are swellable packers, in that they include a material which swells when exposed to an activating fluid. However, other types of packers (e.g., external casing packers, inflatable packers, mechanically or hydraulically set packers, etc.) may be used, and other means of isolating the zones 16 from each other (e.g., cement, gel, etc.) may be used, in keeping with the principles of this disclosure.

Although four valves 12, four zones 16 and four packers 20 are depicted in FIG. 1, it should be clearly understood that any number of each of these elements may be used, and it is not necessary for the same number of valves, zones or packers to be used, in keeping with the principles of this disclosure. Indeed, the principles of this disclosure are not limited at all to any of the details of the system 10 and method representatively illustrated in FIG. 1 and described herein.

The valves 12 are preferably similar in some respects to the DELTA STIM (TM) valves marketed by Halliburton Energy Services, Inc. of Houston, Tex. USA. Each such valve can be individually opened in succession by dropping a ball, dart or other plugging device, which engages a seat in a valve. A pressure differential is then applied across the plugging device to open the valve. Different sized seats and plugging devices (smaller to larger in succession from the distal end of the tubular string) are used to provide selectivity as to which valve is opened when a particular plugging device is used.

In the configuration of FIG. 1, the method in which a stimulation operation is performed would proceed as follows:

1. The tubular string 14 is assembled with the valves 12 (initially closed), packers 20, a landing collar 22 and a valve control device 24 interconnected therein. The lowermost valve 12 a is preferably of the type which opens in response to pressure applied to the tubular string 14, without any plug being installed in the tubular string. The other valves 12 b-d are preferably of the type which open in response to an appropriately sized plug being sealingly engaged with a seat therein, and a pressure differential being applied across the plug. The valves 12 b-d are positioned so that the smallest seat is farthest from the surface, and then in succession from smallest to largest.

2. The tubular string 14 is installed in the wellbore 18, so that the valves 12 are adjacent the respective zones 16.

3. An activating fluid is pumped through the tubular string 14 and into an annulus 26 formed radially between the tubular string and the wellbore 18. This will initiate swelling of the packers 20. Of course, if swellable packers are not used, then there is no need for circulating an activating fluid to the packers.

4. A dart follows the activating fluid and lands in the landing collar 22, thereby sealing off the lower end of the tubular string 14. The tubular string 14 is then pressure tested.

5. If a liner hanger 28 is used, it is now set. Then sufficient time is allowed for the packers 20 to swell into sealing contact with the wellbore 18.

6. The lowermost valve 12 a is opened by applying a predetermined pressure to the tubular string 14. The corresponding zone 16 a is treated by flowing fluids through the tubular string 14, out through the open valve 12 a, and into the zone 16 a.

7. After the zone 16 a treatment is completed, a first plug is dropped at the beginning of the pad of the next zone's 16 b treatment and is pumped down to land in the seat of the valve 12 b. When the plug lands, the zone 16 a is isolated from the treatment fluids delivered to the zone 16 b, a pressure differential applied across the first plug causes the valve 12 b to open, and treatment of the zone 16 b commences.

8. The preceding step is repeated for each of the next zones 16 c, 16 d, with a larger plug being landed in each of the valves 12 c, 12 d when it is desired to treat the corresponding zone.

9. At the end of the stimulation operation, all of the plugs are flowed to the surface. All of the valves 12 a-d are now open and available for production or injection flow. If full bore access is desired, the ball seats in the valves 12 b-d may be drilled or milled through. However, if the ball seats are drilled or milled through, then the valves 12 b-d can later be closed as described below, but the valves cannot then be individually reopened using plugs landed in each of the valves—they will either need to be reopened together (e.g., using the valve control device 24 configuration of FIG. 4), or individually reopened via intervention (e.g., using a mechanical or hydraulic shifting tool).

10. If a further selective stimulation operation is desired, all of the valves 12 b-d can be again closed by use of the valve control device 24. A plug is installed in the device 24, so that it sealingly engages a seat therein, and a pressure differential is applied across the plug, thereby closing all of the valves 12 b-d (preferably simultaneously). The valves 12 b-d can then be opened individually, if needed, for individual treatments of the corresponding zones 16 b-d.

Note that the device 24 is connected to actuators of each of the valves 12 b-d by lines 30. These lines 30 provide flow paths to each of the actuators of the valves 12 b-d. Although the lines 30 are depicted in FIG. 1 as being external to the tubular string 14, it will be appreciated that they could be formed in a sidewall of the tubular string, etc.

Although the method is described above as being performed for a stimulation operation, the valves 12 may be used in other types of operations (e.g., production, conformance, injection, steam flood, geothermal, etc.) in keeping with the principles of this disclosure.

Referring additionally now to FIGS. 2A & B, one of the valves 12 is representatively illustrated at an enlarged scale, apart from the remainder of the well system 10. It should be understood, however, that the valve 12 could be used in other well systems and methods in keeping with the principles of this disclosure. For example, it is not necessary for the valve 12 to be used in a stimulation operation, or for the valve to be used with any particular number of other valves in a tubular string, etc.

The valve 12 includes a sliding sleeve 32 which can be displaced between open and closed positions by various means. The valve 12 can be opened or closed mechanically using internal shifting profiles 34. The valve 12 can be opened by sealingly engaging a plug 36 with a seat 38, and applying a pressure differential across the plug. The valve 12 can also be opened or closed by applying pressure differentials across a piston 40.

The piston 40 is part of an actuator 42 of the valve 12. The actuator 42 also includes chambers 44, 46 on opposite sides of the piston 40. The chambers 44, 46 are connected to flow paths 30 a and 30 b of the lines 30, thereby connecting the valve 12 to the device 24, and enabling a pressure differential to be applied across the piston 40 to actuate the valve between its open and closed configurations.

Note that the valve 12 is depicted in FIGS. 2A & B in its open configuration (after a pressure differential has been applied across the plug 36 to thereby shift the sleeve 32 to its open position). The plug 36 may then be circulated out of the valve 12, if desired.

To close the valve 12, a pressure differential can be applied from the chamber 46 to the chamber 44 to thereby bias the piston 40 to displace the sleeve 32 to its closed position. To open the valve 12, a pressure differential can be applied from the chamber 44 to the chamber 46 to thereby bias the piston 40 to displace the sleeve 32 to its open position.

Referring additionally now to FIG. 3, an enlarged scale view of the valve control device 24 is representatively illustrated, apart from the remainder of the well system 10. It should be understood, however, that the device 24 could be used in other well systems and methods in keeping with the principles of this disclosure. For example, it is not necessary for the device 24 to be used in a stimulation operation, or for the device to be used with any particular number of valves in a tubular string, etc.

In this view it may be seen that the device 24 has the flow paths 30 a, 30 b connected thereto, with a seat 48 formed longitudinally between ports 50, 52 connecting an interior flow passage 54 to the respective flow paths. It will be appreciated that, if a plug 56 is sealingly engaged with the seat 48, then pressure applied to the tubular string 14 above the device 24 will generate a pressure differential across the plug, and will generate a pressure differential from the flow path 30 b to the flow path 30 a.

If the plug 56 is not sealingly engaged with the seat 48, the flow paths 30 a, 30 b will be pressure balanced. This is preferred, so that pressure fluctuations in the interior of the tubular string 14 (in the passage 54) do not cause inadvertent operation of the actuator 42.

When the plug 56 is sealingly engaged with the seat 48, and pressure is increased in the passage 54 above the plug, fluid in the flow path 30 a is permitted to flow into the passage below the plug via the port 50. This enables the piston 40 to displace the sleeve 32 to its closed position in response to the pressure differential created from the chamber 46 to the chamber 44, thereby exhausting fluid from the chamber 44.

Referring additionally now to FIG. 4, another configuration of the device 24 is representatively illustrated. In this configuration, the seat 48 is in the form of a seal bore, and a different plug 56 is used. The plug 56 directs pressure from the passage 54 above the plug to the port 50, and communicates the port 52 with the passage 54 below the plug.

Using the plug 56, the valve 12 can be closed by applying increased pressure to the interior of the tubular string 14 (in the passage 54) above the plug 56. The increased pressure will generate a pressure differential from the chamber 44 to the chamber 46 in the valve 12, thereby biasing the piston 40 to displace the sleeve 32 to its open position.

As the sleeve 32 displaces, fluid in the chamber 46 will be exhausted to the passage 54 below the plug 56 via the port 52. It will be appreciated that another plug (similar to the plug 56) could be easily constructed, so that the plug would communicate the port 52 to the passage 54 above the plug, and would communicate the port 50 to the passage below the plug (similar to the configuration of FIG. 3).

Referring additionally now to FIG. 5, another configuration of the valve control device 24 is representatively illustrated. The device 24 of FIG. 5 is similar to the device of FIG. 3, in that it includes the tapered seat 48, instead of the cylindrical seat of FIG. 4. However, the device 24 of FIG. 5 is also similar to the device of FIG. 4, in that it includes seal bores 60, 62 straddling the seat 48 and ports 50, 52.

As depicted in FIG. 5, a test plug 64 is installed in the device 24 for pressure testing the device and flow paths 30 a, 30 b during installation in a well. The test plug 64 includes a latch 66 which engages a latch profile 68 in the device 24, so that the test plug remains secured in the device during the pressure testing.

Pressure is applied via an external port 70 in communication with the flow passage 54 longitudinally between seals 72 carried on the test plug 64. Thus, pressure applied via the port 70 will be communicated to the flow paths 30 a, 30 b via the ports 50, 52.

After pressure testing, the test plug 64 is removed from the device 24. The port 70 is plugged prior to lowering the device 24 into the well. After installation, the plug 56 may be engaged with the seat 48 to open and/or close the valves 12 b-d as described above.

Note that any of the features of any of the configurations of the valve control device 24 described above may be included, or substituted for, any of the features of any of the other configurations of the device. For example, the configuration of FIG. 5 could be provided with the cylindrical seat 48 of the configuration of FIG. 4, the seal bores 60, 62 and latch profile 68 could be provided in the configuration of FIG. 3, etc.

In any of the configurations described above, after the valves 12 b-d have been successfully opened or closed, as desired, the plug 56 can be circulated out of the tubular string 14. If the valves 12 b-d were closed, then at this point, the valves 12 b-d can be individually opened using the plugs 36 as described above, allowing for repeated selective stimulation, etc.

It may now be fully appreciated that the above disclosure provides several advancements to the art of controlling operation of multiple valves in a well. By interconnecting the device 24 to the actuators 42 of the valves 12, the valves can be conveniently, economically and quickly closed when desired. The device 24 can also be used to open the valves 12. The valves 12 can be simultaneously closed and/or opened, if desired.

The above disclosure provides to the art a method of controlling operation of multiple valves 12 b-d interconnected in a tubular string 14 in a subterranean well. The method can include opening each of the valves 12 b-d, and then closing the valves 12 b-d in response to an application of pressure to the tubular string 14.

Closing the valves 12 b-d can include closing all of the valves 12 b-d in response to only the single application of pressure to the tubular string 14.

Closing the valves 12 b-d can include closing all of the valves 12 b-d simultaneously in response to the application of pressure to the tubular string 14.

The method may include installing a plug 56 in the tubular string 14 after opening each of the valves 12 b-d, and prior to closing the valves 12 b-d. Installing the plug 56 can include sealing the plug 56 in a valve control device 24 connected via at least one flow path 30 a, 30 b to an actuator 42 of each of the valves 12 b-d. Closing the valves 12 b-d may include generating a pressure differential across the plug 56, the pressure differential also being generated in the actuator 42 of each of the valves 12 b-d, thereby closing the valves.

The method can include, after closing the valves 12 b-d, then opening the valves in response to another application of pressure to the tubular string 14. Opening the valves 12 b-d after closing the valves may include opening all of the valves simultaneously.

The method can include installing a plug 56 in the tubular string 14 after closing the valves 12 b-d. Opening the valves 12 b-d after closing the valves may include generating a pressure differential across the plug 56, the pressure differential also being generated in an actuator 42 of each of the valves 12 b-d, thereby opening the valves.

Also provided by the above disclosure is a well system 10. The well system 10 can include multiple valves 12 b-d interconnected in a tubular string 14, each of the valves including an actuator 42, and a valve control device 24 interconnected in the tubular string 14. The valve control device 24 is connected to each of the valve actuators 42 via multiple flow paths 30 a, 30 b, whereby a pressure differential generated between the flow paths 30 a, 30 b is also generated in each of the valve actuators 42.

The well system 10 may also include a plug 56 which sealingly engages a seat 48 in the valve control device 24. The seat 48 may be disposed between the flow paths 30 a, 30 b in the valve control device 24, whereby the pressure differential generated between the flow paths 30 a, 30 b is generated across the plug 56.

Each of the valves 12 b-d may also include a seat 38, which is sealingly engaged by a plug 36 to thereby open the valve. Each of the valves 12 b-d can be opened by an application of pressure to the tubular string 14 when the respective plug 36 is sealingly engaged with the corresponding seat 38.

The pressure differential generated between the flow paths 30 a, 30 b may open the valves 12 b-d. The valves 12 b-d may open simultaneously in response to the pressure differential generated between the flow paths 30 a, 30 b.

The pressure differential generated between the flow paths 30 a, 30 b may close the valves 12 b-d. The valves 12 b-d may close simultaneously in response to the pressure differential generated between the flow paths 30 a, 30 b.

The pressure differential generated between the flow paths 30 a, 30 b may open the valves 12 b-d when one plug 56 is sealingly engaged in the valve control device 24, and the pressure differential generated between the flow paths 30 a, 30 b may close the valves 12 b-d when another plug 56 is sealingly engaged in the valve control device 24.

It is to be understood that the various examples described above may be utilized in various orientations, such as inclined, inverted, horizontal, vertical, etc., and in various configurations, without departing from the principles of the present disclosure. The embodiments illustrated in the drawings are depicted and described merely as examples of useful applications of the principles of the disclosure, which are not limited to any specific details of these embodiments.

In the above description of the representative examples of the disclosure, directional terms, such as “above,” “below,” “upper,” “lower,” etc., are used for convenience in referring to the accompanying drawings. In general, “above,” “upper,” “upward” and similar terms refer to a direction toward the earth's surface along a wellbore, and “below,” “lower,” “downward” and similar terms refer to a direction away from the earth's surface along the wellbore.

Of course, a person skilled in the art would, upon a careful consideration of the above description of representative embodiments, readily appreciate that many modifications, additions, substitutions, deletions, and other changes may be made to these specific embodiments, and such changes are within the scope of the principles of the present disclosure. Accordingly, the foregoing detailed description is to be clearly understood as being given by way of illustration and example only, the spirit and scope of the present invention being limited solely by the appended claims and their equivalents. 

1. A method of controlling operation of multiple valves interconnected in a tubular string in a subterranean well, the method comprising: opening each of the valves; and then closing the valves in response to an application of pressure to the tubular string.
 2. The method of claim 1, wherein closing the valves further comprises closing all of the valves in response to only the single application of pressure to the tubular string.
 3. The method of claim 1, wherein closing the valves further comprises closing all of the valves simultaneously in response to the application of pressure to the tubular string.
 4. The method of claim 1, further comprising installing a plug in the tubular string after opening each of the valves, and prior to closing the valves.
 5. The method of claim 4, wherein installing the plug further comprises sealing the plug in a valve control device connected via at least one flow path to an actuator of each of the valves.
 6. The method of claim 5, wherein closing the valves further comprises generating a pressure differential across the plug, the pressure differential also being generated in the actuator of each of the valves, thereby closing the valves.
 7. The method of claim 1, further comprising, after closing the valves, then opening the valves in response to another application of pressure to the tubular string.
 8. The method of claim 7, wherein opening the valves after closing the valves further comprises opening all of the valves simultaneously.
 9. The method of claim 7, further comprising installing a plug in the tubular string after closing the valves.
 10. The method of claim 9, wherein opening the valves after closing the valves further comprises generating a pressure differential across the plug, the pressure differential also being generated in an actuator of each of the valves, thereby opening the valves.
 11. A well system, comprising: multiple valves interconnected in a tubular string, each of the valves including an actuator; and a valve control device interconnected in the tubular string, the valve control device being connected to each of the valve actuators via multiple flow paths, whereby a pressure differential generated between the flow paths is also generated in each of the valve actuators.
 12. The well system of claim 11, further comprising a plug which sealingly engages a seat in the valve control device.
 13. The well system of claim 12, wherein the seat is disposed between the flow paths in the valve control device, whereby the pressure differential generated between the flow paths is generated across the plug.
 14. The well system of claim 11, wherein each of the valves further includes a seat, which is sealingly engaged by a plug to thereby open the valve.
 15. The well system of claim 14, wherein each of the valves is opened by an application of pressure to the tubular string when the respective plug is sealingly engaged with the corresponding seat.
 16. The well system of claim 11, wherein the pressure differential generated between the flow paths opens the valves.
 17. The well system of claim 16, wherein the valves open simultaneously in response to the pressure differential generated between the flow paths.
 18. The well system of claim 11, wherein the pressure differential generated between the flow paths closes the valves.
 19. The well system of claim 18, wherein the valves close simultaneously in response to the pressure differential generated between the flow paths.
 20. The well system of claim 11, wherein the pressure differential generated between the flow paths opens the valves when a first plug is sealingly engaged in the valve control device, and wherein the pressure differential generated between the flow paths closes the valves when a second plug is sealingly engaged in the valve control device. 